The Inhaled Corticosteriod Study (ICS) is a proposed multicenter randomized clinical trial designed to determine whether daily use of inhaled corticostoids, in middle-aged men and women with impaired lung function, can reduce the rate of decline of FEV1 over a 3 1/2 to 4 1/2- year follow-up period. The present proposal on behalf of the Division of Biostatistics of the University of Minnesota is for the establishment and operation of the Lead Center (at Johns Hopkins University in Baltimore) and for 10 participating clinical centers. Specific objectives for the DCC in this study include the following: 1) Participate in finalization of ICS protocol, Manual of Procedures, spirometry software, and data collection forms 2) Implement systems for eligibility verification, data collection, data management and data quality assurance 3) Produce regular interim reports on recruitment, follow-up, adherence to protocol, adverse conditions, endpoint results, morbidity and mortality, and data quality 4) Participate in training of study personnel and periodic inspection of clinic sites 5) Perform statistical analysis of, and prepare detailed reports on, study data for publications and presentations and for monitoring by the study's Safety and Data Monitoring Board 6) Participate in authorship of study publications The proposed study is a natural outgrowth of the Lung Health Study (LHS). Staff for the proposed ICS have had extensive experience in the DCC for the LHS and other multicenter clinical trials. They bring methodology, statistics, data collection, management and analysis, data monitoring and reporting, and all other aspects of clinical trials operation.